From 1923 to 1986, American automobiles ran on ethyl, a gasoline that prevented engine knock due to its lead content. Within days of its introduction, refinery workers began dying. However, the oil industry managed to explain away the deaths and quash investigations into lead’s effect on people and the environment. A scientist named Dr. Clair Patterson noticed how lead contamination affected his research, and waged a decades-long campaign against ethyl which finally led to the Clean Air Act of 1970. Read the entire fascinating story at Damn Interesting. Link

1986? You would be pretty hard pressed to find any pump gasoline sold with lead at that time. Catalytic converters have been used on virtually all US-sold cars since 1975 (early Honda CVCC engined cars being an exception). All of these cars had to use unleaded gasoline.